On 11/03/2014 10:13 AM, Thierry Reding wrote:
From: Thierry Reding treding@nvidia.com
This commit introduces a new function, mipi_dsi_create_packet(), which converts from a MIPI DSI message to a MIPI DSI packet. The MIPI DSI packet is as close to the protocol described in the DSI specification as possible and useful in drivers that need to write a DSI packet into a FIFO to send a message off to the peripheral.
Suggested-by: Andrzej Hajda a.hajda@samsung.com Signed-off-by: Thierry Reding treding@nvidia.com
drivers/gpu/drm/drm_mipi_dsi.c | 45 ++++++++++++++++++++++++++++++++++++++++++ include/drm/drm_mipi_dsi.h | 18 +++++++++++++++++ 2 files changed, 63 insertions(+)
diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c index eb6dfe52cab2..76e81aba8220 100644 --- a/drivers/gpu/drm/drm_mipi_dsi.c +++ b/drivers/gpu/drm/drm_mipi_dsi.c @@ -199,6 +199,51 @@ int mipi_dsi_detach(struct mipi_dsi_device *dsi) EXPORT_SYMBOL(mipi_dsi_detach);
/**
- mipi_dsi_create_packet - create a packet from a message according to the
DSI protocol
- @packet: pointer to a DSI packet structure
- @msg: message to translate into a packet
- Return: 0 on success or a negative error code on failure.
- */
+int mipi_dsi_create_packet(struct mipi_dsi_packet *packet,
const struct mipi_dsi_msg *msg)+{
- const u8 *tx = msg->tx_buf;
- if (!packet || !msg)
return -EINVAL;- memset(packet, 0, sizeof(*packet));
- packet->header[0] = ((msg->channel & 0x3) << 6) | (msg->type & 0x3f);
- /* TODO: compute ECC if hardware support is not available */
- /*
* Long write packets contain the word count in header bytes 1 and 2.* The payload follows the header and is word count bytes long.** Short write packets encode up to two parameters in header bytes 1* and 2.*/- if (msg->tx_len > 2) {
This is incorrect, you can have long packet of payload length 0, look for "zero-byte Data Payload" phrase. I think you should check msg->type here.
I have used:
static bool exynos_dsi_is_short_dsi_type(u8 type) { return (type & 0x0f) <= 8; }
quite ugly, but works :)
packet->header[1] = (msg->tx_len >> 0) & 0xff;packet->header[2] = (msg->tx_len >> 8) & 0xff;packet->payload_length = msg->tx_len;packet->payload = tx;- } else {
packet->header[1] = (msg->tx_len > 0) ? tx[0] : 0;packet->header[2] = (msg->tx_len > 1) ? tx[1] : 0;- }
- packet->size = sizeof(packet->header) + packet->payload_length;
size seems to be completely useless.
- return 0;
+} +EXPORT_SYMBOL(mipi_dsi_create_packet);
+/**
- mipi_dsi_dcs_write - send DCS write command
- @dsi: DSI device
- @data: pointer to the command followed by parameters
diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h index 8569dc5a1026..663aa68826f4 100644 --- a/include/drm/drm_mipi_dsi.h +++ b/include/drm/drm_mipi_dsi.h @@ -44,6 +44,24 @@ struct mipi_dsi_msg { };
/**
- struct mipi_dsi_packet - represents a MIPI DSI packet in protocol format
- @size: size (in bytes) of the packet
- @header: the four bytes that make up the header (Data ID, Word Count or
Packet Data, and ECC)
- @payload_length: number of bytes in the payload
- @payload: a pointer to a buffer containing the payload, if any
- */
+struct mipi_dsi_packet {
- size_t size;
- u8 header[4];
I wonder if it wouldn't be good to make it u32 or at least anonymous union: union { u8 header[4]; u32 header32; };
And of course we should document its endiannes. This way we can use le16_to_cpu(pkt->header32) instead of constructing u32 value from array.
Regards Andrzej
- size_t payload_length;
- const u8 *payload;
+};
+int mipi_dsi_create_packet(struct mipi_dsi_packet *packet,
const struct mipi_dsi_msg *msg);+/**
- struct mipi_dsi_host_ops - DSI bus operations
- @attach: attach DSI device to DSI host
- @detach: detach DSI device from DSI host